Building confidence in your shoulders means having a solid strengthening routine for your deltoids, which form a cover or "cuff" around the head of the humerus, reminiscent of a shoulder pad. The deltoids get help from upper and lower trapezius, serratus, and pectorals, so those have to be addressed as well in shoulder maintenance.

Of course everything is connected, the body must be thought of as a fully functioning team, the core and legs play their part in healthy shoulders too.

In this video I do 3 sets of exercises to strengthen the shoulders and all the team players. I use 8 lb weights that I worked up to, beginning with 3 lb many years ago. I highly recommend that you start with light weights and work your way up. Each time you do this routine there should be awareness of your shoulder muscles and definition developing of the shoulder pads (or the cuff) that are your deltoids. When you stop feeling that awareness it's time to grab heavier weights next time.